Internet service providers BT and TalkTalk have lost their appeal against the UK's Digital Economy Act. The ISPs had argued that the legislation was incompatible with EU law, but this morning the Court of Appeal decided otherwise and dismissed their appeal. While the decision was welcomed by copyright holders, Internet account holders now face warnings, disconnections and speed throttling.

For almost a year the UK’s Digital Economy Act has been in limbo after two of the country’s largest Internet service providers challenged the legislation. BT and TalkTalk had argued that the controversial law was incompatible with EU legislation and in March 2011 the High Court began a judicial review.

In April 2011 the High Court sided with the government and said that copyright holders have the right to tackle unlawful file-sharing, but in October the ISPs were granted leave to appeal on the grounds that the DEA might breach several EU directives.

Just minutes ago judges Lady Justice Arden, Lord Justice Richards and Lord Justice Patten declared that the ISPs have lost their appeal and the Digital Economy Act will stand.

TalkTalk described the ruling as “disappointing” and along with BT say they are now considering their options. Groups representing copyright holders have welcomed the Court of Appeal ruling.

“The ISPs’ failed legal challenge has meant yet another year of harm to British musicians and creators from illegal filesharing,” said Geoff Taylor, chief executive of the BPI.

UK Internet service providers will now be required to send warning letters to customers who the music, movie and software industries claim are infringing their copyrights on file-sharing networks.

After a year of sending letters, communications regulator Ofcom must report on the results of the campaign. In the event it has been ineffective in reducing file-sharing, so-called “technical measures” can be put in place – a euphemism for Internet disconnections and/or Internet throttling.

Open Rights Group, who have been campaigning against the legislation, said the Court of Appeal ruling has shortcomings.

“There is one thing the court cannot tell us: that this is a good law. The Department for Culture, Media and Sport had no evidence when they wrote this Act, except for the numbers they were given by a couple of industry trade bodies. This is a policy made on hearsay and assumptions, not proper facts or analysis,” ORG’s Peter Bradwell said in a statement.

“So significant problems remain. Publicly available wifi will be put at risk. Weak evidence could be used to penalize people accused of copyright infringement. And people will have to pay £20 for the privilege of defending themselves against these accusations. The Government needs to correct these errors with a proper, evidence-based review of the law.”

In comments to the BBC, Adam Rendle, a copyright lawyer at international law firm Taylor Wessing, said he expected BT and Talk Talk to take their appeal to the UK’s Supreme Court.